Reflection probe array can exceed the driver's per-allocation limit (maxMemoryAllocationSize) #1081

New issue

Open

opened 2026-10-25 20:55:47 +00:00 by sky_line · 0 comments

sky_line commented

2026-10-25 20:55:47 +00:00

Owner

Validation Error: [ UNASSIGNED-vkAllocateMemory-maxMemoryAllocationSize ]
vkAllocateMemory(): pAllocateInfo->allocationSize (4303355904) is larger than maxMemoryAllocationSize (4292870144).

The VRAM check (vramPick, called from configureProbes) only compares against free VRAM, so it reported "fits". NVIDIA accepts it anyway; drivers that enforce the limit refuse it and the soft allocation falls back to a smaller set (no crash), but it is still out of spec.

Fix: query VkPhysicalDeviceMaintenance3Properties::maxMemoryAllocationSize once at device init and make vramPick (or the probe candidate list) skip any candidate whose largest single allocation exceeds it. Check other large single allocations (shadow atlases, GI/ReSTIR buffers, the vis queue) against the same limit.

Found by the automated validation run on the 1.5 candidate (GTX 1080): setting reflection probes to 256 slots at 512 resolution allocates the probe array as one 4.30 GB image; the device's `maxMemoryAllocationSize` is 4.29 GB. ``` Validation Error: [ UNASSIGNED-vkAllocateMemory-maxMemoryAllocationSize ] vkAllocateMemory(): pAllocateInfo->allocationSize (4303355904) is larger than maxMemoryAllocationSize (4292870144). ``` The VRAM check (`vramPick`, called from `configureProbes`) only compares against free VRAM, so it reported "fits". NVIDIA accepts it anyway; drivers that enforce the limit refuse it and the soft allocation falls back to a smaller set (no crash), but it is still out of spec. Fix: query `VkPhysicalDeviceMaintenance3Properties::maxMemoryAllocationSize` once at device init and make `vramPick` (or the probe candidate list) skip any candidate whose largest single allocation exceeds it. Check other large single allocations (shadow atlases, GI/ReSTIR buffers, the vis queue) against the same limit.

sky_line added the

bug

rendering

labels

2026-10-25 20:55:47 +00:00

sky_line added this to the Slipstream project

2026-10-25 20:55:47 +00:00

sky_line self-assigned this

2026-10-26 02:58:27 +00:00